When beer or malt based fermented beverages (collectively referred to herein as “beer”) and fermented beverages in general, such as cider, are widely distributed stored in bottles and metal cans, there is a marked preference by the public for beers served directly on tap from a keg, referred to as draught (or draft) beer. Since draught beer was traditionally served in large volumes in public houses (pubs) and restaurants, large capacity metal kegs were traditionally used, typically 50 l kegs (=11 Imperial gallons). In recent years, however; a reduction of the kegs capacity offered on the market has been observed. There are two main factors explaining this trend.
First, brewers have developed various solutions for offering draught beer to particulars with specifically designed home appliances. It is clear that if 50 l kegs can be emptied reasonably rapidly in a pub, this is not the case for home appliances. Hence, smaller kegs of 5 to 15 l capacity were developed. Such home appliances are often referred to as “table top dispensers” or “counter top dispensers” because they are small enough to stand on top of a table or a counter.
Second, even in pubs, the tastes of the consumers have shifted from traditional lager beers towards special beers, with more specific flavours. This diversification of the types of beers offered for consumption in pubs has pushed brewers to store their special beers in smaller capacity kegs, ranging from 8 to 25 l kegs. Though counter top dispensers are often used with kegs of up to 15 l capacity, larger kegs of up to the order of 18 or 25 l capacity are too large to stand on top of a counter, and probably too small to justify storing them in a basement far away from the tap, they are usually stored directly under the tapping column, usually in a refrigerated chamber. For this reason and by opposition to the expression “table top dispensers”, such dispensing systems used in pubs are often referred to as “under the counter dispensers”.
With the reduction of kegs capacity, however, the cost of packaging (i.e. cost of keg per liter of beer sold) increased accordingly. Alternative solutions to metal kegs had to be developed, typically replacing metal kegs by polymeric kegs made for example of PET. Furthermore, since draught beers require a pressurized gas to drive the dispensing of the beer out of the keg, and pressurized CO2 bottles used in pubs are not readily available or not practical for home appliances, solutions were proposed to use air compressors as source of pressurized gas instead. To avoid any contact between air and beer, dispensing bag-in-containers have been used, wherein the beer is contained in a flexible inner bag contained in an outer, rigid container, and pressurized gas is injected into the space between the inner bag and outer container to collapse the inner bag and drive the beer out of the bag. As illustrative examples, integrally blowmoulded polymeric dispensing bag-in-containers are disclosed in WO2008129018, WO2008129016, WO2008129012, WO2008129015, or WO2008129013, which contents are herein incorporated by reference.
Regardless of its size, before use a beer keg must be connected to a dispensing line and to a source of pressurized gas. Home appliances have been designed with their own specific solution for rapidly connecting a dispensing line and a gas source to the interior of the kegs (cf. e.g., WO2012056018). In some cases, the source of pressurized gas is stored in the keg itself, but this solution is rather expensive and to date implementable in quite small kegs only (cf. e.g., WO9947451, WO2007/108684). In pubs, however, although the kegs designs have changed dramatically as discussed above, the same equipment as for large 50 l kegs is often still being used downstream from the keg, including the keg connector, the dispensing tube, dispensing valve, gas duct, and draught column and tap.
With smaller kegs available with a variety of beer types, it is likely that a beer dispensing appliance will be loaded with kegs containing different types of beers more often than with larger, traditional kegs. All the elements of the dispensing appliance contacting the beer and located downstream from the keg, including the dispensing tube, the dispensing valve and, optionally, the keg connector, shall consequently be changed more often, to avoid flavours mixing between two types of beer. A dispensing tube is often provided with each new keg, so that it shall be disposed of together with the empty keg after use. In some cases, the keg is sold with the dispensing tube irreversibly coupled to the keg or, alternatively, the dispensing tube can be coupled to the keg by means of a keg connector. Traditional keg connectors are made of metal. New keg connectors are now being developed which are cheaper, simpler, and often made of polymer, such as disclosed in WO2014057099, some keg connector are even disposable such as disclosed in EP 2923998 and EP 2987767.
Beer contained in a keg is pressurized by injecting pressurized gas into the keg, either in the headspace on top of the beer level, or in the space between outer container and inner bag in bag-in-containers. The pressurized liquid flows through the dispensing tube. In order to control the flow of liquid out of the dispensing tube, a dispensing valve is used. It is generally activated by rotation of a lever at the end of a tapping column as well known in the art. Different types of dispensing valves are currently used.
A much appreciated type of valve is a pinch valve, wherein a resilient portion of the dispensing tube is inserted between two jaws which can be moved towards and away from each other to, respectively, interrupt or allow the flow of liquid through the thus pinched resilient portion of the dispensing tube. This type of valves is very appreciated because the mechanical elements of the valve never contact the liquid flowing through the dispensing tube. Examples of such pinch valves are disclosed in WO2013164258 and WO2012062609. The inconvenience with pinch valves is that they limit the choice of materials to be used for the dispensing tube to materials having sufficient flexibility and resilience to function properly with a pinch valve and the flow rate is not very accurate.
Alternatively, stopcocks (or plug valves) can be used for the control of beer flow through the dispensing tube. A stopcock comprises a plug provided with a through channel which is rotatably mounted in a housing coupled to an inlet portion and an outlet portion of a dispensing tube. The rotation of the plug brings the through channel in or out of fluid communication with the inlet and outlet portions of the dispensing tube. Stopcocks made of glass are widely used in laboratories as they afford an accurate control of the flow of a liquid. Since the liquid flows through the through-channel in the plug, a stopcock must be cleaned thoroughly after use or changed together with the dispensing tube every time a new type of beer is loaded in the dispenser, or every time the dispenser has not been used and contamination may have developed in the dispensing tube. In order to be implementable in beverage dispensers, the production cost of stopcocks must be reduced substantially.
WO2004018915 discloses a stopcock for use in medico-surgical drainage systems. A housing is injection moulded comprising a peripheral wall defining a central cylindrical portion flanked at each end by a trunco-conical portion flaring out with increasing diameter, like a thread spool. A plug is injection moulded into the cylindrical chamber and caused to shrink more than the housing, such that the trunco-conical portion of the housing peripheral wall impedes the plug to shrink uniformly. After cooling, the plug cross-section deviates from circularity. The rotation of a non-circular plug within a cylindrical central portion of the housing allows the formation of a strong contact between the walls of the plug and the housing peripheral wall which seal the stopcock. The stopcock disclosed in WO2004018915 was tested in a beverage dispenser, but the stopcock did not resist the pressures of the order of 0.5 to 1.5 bar above atmospheric, used in beverage dispensing appliances, which are much higher than the ones associated with medico-surgical drainage systems, and liquid seeped between the plug and the housing peripheral wall.
FR1290315 discloses a stopcock comprising a plug rotatingly mounted in a chamber comprising an inlet orifice and an outlet orifice. The plug comprises a through channel extending from one inlet opening to an outlet opening—both openings being located at a peripheral wall of said plug—, such that by rotation of the plug, the inlet opening and the outlet opening of the plug are brought into or out of registry with the inlet orifice and outlet orifice of the chamber, respectively. The plug peripheral wall further comprise two closed-loop shaped protrusions defining two blank areas of the peripheral wall of the plug, such that when the plug's inlet and outlet openings are out of registry with the chamber's inlet and outlet orifices, the latter two orifices face the blank areas of the plug's peripheral wall, thus ensuring a fluid tight contact between the plug and the chamber in closed position. This solution is interesting, but the problem is that with the protrusions defining the blank areas, the fluid tightness is worsened in any position wherein said protrusions do not circumscribe the chamber's inlet and outlet orifices, since said protrusion distort the rotational symmetry of the plug.
There therefore remains a need in the art for a stopcock which is reliable at the pressures typically used in beverage dispensing appliances, which is reliable and which production cost is compatible with disposable valves. The present invention proposes such stopcock. These and other advantages of the present invention are presented in the next sections.